It's hard to say what to do, not because there's so much at stake, but because the choice is largely immaterial.
Leveling is very fast (you can max a class in perhaps a week if you try), making the value supplied by crafters and gatherers rather minimal in the larger context. That is, a few months from now most everyone is going to have several of these classes at 50. You need these classes to, say, meld materia or craft relic weapons, but at the same time you really could just do it yourself after a few weeks of grinding. Thus the reliance upon them (or others' reliance on you, depending on your perspective) isn't so great unless you're rushing to accomplish the game's loftiest goals within the first month of release.
There's plenty of gil to be made crafting and gathering, but at the same time the game inundates you with gil, so ultimately it's more an "easy come, easy go" scenario. Buy what you want from others, or spend the gil to level your own means to do so. Crafting will make you more self-sufficient, but there's not a pressing need for self-sufficiency, as materials (and undercutting individuals) are abundant.
In the long run, with most everyone having these classes capped, the choice won't matter too much, and it's more akin to personal preference.
____________________________"... he called to himself a wizard, named Gallery, hoping by this means to escape the paying of the fifteen hundred crowns..." (Machen 15) "Thus opium is pleasing... on account of the agreeable delirium it produces." (Burke para.6) "I could only read so much for this paper and the syphilis poem had to go."